No worries, we're always happy to read long comments! :) As Kazuya's writer, I'm really glad to hear you enjoyed playing his route! I'm a big fan of tsunderes and I agree it can be annoying when they're mean for no reason. I wanted to make sure Kazuya had his personal reasons for his behaviour and that he also owns up to it eventually, and I'm happy to see that seems to have worked! I hope you'll enjoy the fifth ending as well.
And as mentioned before, we'll definitely consider Sora bonus content/extended epilogues/after-stories since there seems to be a lot of interest but only time can tell if we do end up releasing some extra content. If we do, it won't be soon anyway, but we really appreciate the interest and we'll keep you guys posted if it does happen! ✨